Backwater valve



Patented Oct. 15, 1946 UNITED STATES PATENT OFFICE BACKWATER VALVE Samuel Olson, Chicago, Ill.

Application October 26, 1944, Serial No. 560,444 s claims. (o1. 18a-1) 1 This invention relates to drainage systems, particularly as employed in domestic and industrial buildings, for discharging waste matter and water into municipal sewer systems or other drainage' facilities.

One object of the invention is to prevent the sewer water from backing up under flood conditions and overflowing into the various waste outlets in a building. p

Another object of the invention is to provide automatic means responsive to an excessive rise in the level of the water in a sewer and operative to close a valve controlling a drain pipe connecting the sewer with a building.

A further object of the invention is to provide a back water valve for the purpose indicated arranged to be moved slidably onto its seat with a self cleaning action for removing accumulated debris or other matter encrusted on the valve seat.

It is also an object of the invention to provide, in a drain passage leading from a building to a sewer or other outlet, a chamber closed except for an inlet and. outlet by which it is connected into the passage, and containing a float responsive to liquid level in the chamber, a valve mounted for movement into position to close the inlet and operative connections between the float and the valve by which the valve is closed when the level of liquid within the chamber exceeds a predetermined limit.

Other objects and advantages of the invention will appear from the following description taken in connection with the drawing in which Fig. l is a vertical sectional view of a chamber arranged in accordance with this invention and including a back water valve and a oat connected for operating the same, the section being taken substantially as indicated at line I--I on Fig. 2.

Fig. 2 is a vertical section taken substantially as indicated at line 2 2 on Fig. 1 and with the valve in open position.

Fig, 3 is a vertical sectional view similar to Fig. 2 but with certain parts shown in elevation and with the valve shown in closed position.

Fig. 4 is a horizontal section taken as indicated at line 4-4 on Fig. 2 and showing the mechanism in plan.

While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications `and rearrangements of the parts may loe-made without departing from the spirit and scope of the invention, and that the.

same is not limited to the particular form herein shown and described, except in so far as indicated by the appended claims.

It is quite common, during a heavy rain storm or in the time of floods, for municipal sewers to become so overtaxed that the water in the sewer rises until it backs up into the drainage conduits leading from homes and other buildings, and overflows onto basement floors or even through drain outlets at more elevated positions in the building, causing great inconvenience and considerable damage. This invention is designed to automatically prevent such occurrences by closing a valve positioned at a relatively low levelinY the drain discharge pipefrom a building so as to prevent the sewer water from rising above that point in the discharge pipe.

The back water valve structure which serves this purpose is enclosed in a chamber I which is interposed in the drain conduit and which has an inlet 2 and an outlet 3. A fragment of the conduit leading from the building is shown at 2a anda fragment of the conduit leading to the sewer is shown at 3a. The inlet is provided with an elbow 4 within the chamber I and terminating in a downwardly discharging opening having a valve seat 5 adapted to be closed by the valve member 6 which is slidable thereover. The valve member is suspended in the chamber I by a pair of links 1, 'I pivotally connected to the Valve at opposite sides thereof as shown at 8, these pivotal connections being aligned at an axis disposed approximately midway between the forward and rear edges of the valve. An additional link 9 is connected to the valve adjacent its rear edge. All the links are swung from a point near the top of the chamber, the link 9 being pivoted to a bracket I0 and the link 'I extending from'a cross bar II v with springs I2 interposed between the cross bar It may be understood that the valve 6 is nory mally open as shown in Fig. 2, with the drainage flowing from the inlet conduit 2e through the inlet 2 and elbow 4 and discharging against the floor I5 of the chamber I. slopes toward the outlet 3 through which the drainage Apasses into the conduit 3%, but in the event of flood conditions, such that the water This floor I5V backs up in the pipe 3a and starts to rise in the chamber 2, a float I6 in the chamber will be elevated as the water level rises therein. rFhis float is guided loosely for vertical movement between one wall of the chamber I and a tra-nsversely extending guide member II and is provided with upwardly extending arms I8, IB connected by a cross bar I9 and pivotally attached to the arms 2S, 2B secured to the rock shaft 2i which extends across the chamber I and is journaled on the side walls thereof as shown in Fig. 1.

The single arm 22 extending downwardly from the rock shaft 2l is connected to the link 9 bya pivot 23 engaging a float I6 thus swings the arms 20, 2U upwardly and rocks the shaft 2| in a direction to swing its arm 22 forward, that is, toward the terminal elbow 4 of the inlet, so that the link 9 is thereby moved in a direction to slide the valve 8 over the seat 5 to the closed position illustrated in Fig. 3.

Since flood conditions which operate to close the valve 6 occur only occasionally there may be some accumulation of debris or solid matter encrusted on the upper surface of the valve E but the valve seat is formed by a flange encircling the terminal outlet of the elbow and the outer edge of this flange is beveled to an acute edge at 5a so that as the valve t slides across the seat 5 the sharp edge 5ab acts to shear from the upper surface of the valve 6 any encrusted accumulation so as to insure effective seating of the valve. This action is assisted by the springs i2 which constantly urge the valve against the seat and into effective engagement with the shearing edge ila as the valve moves across the terminal seat flange 5 toward its closed position. The tension of the springs I2 may be varied by adjustment of the nuts i3 which are readily accessible upon removal of the cover 25 of the chamber I.

It will be noted from Fig. 3 that a comparatively limited rise of the float i6 is sufficient to shift the valve E to its closed position so that the valve will actually close before the flood water enters the inlet conduit 2a leading from the buildof dow. Accordingly, the valve will tend to keep itself clean so that there should be a minimum of encrusted matter on the upper surface of the valve i to be scraped or sheared off by the beveled edge 5ii of the valve seat when flood conditions cause the valve to be moved to its closed position. As a precaution against any possible accumulation on the under side of the valve seat 5, the leading edge of the valve member 8 is beveled to an acute edge as seen at E@ in Figures 2 and 3, so that this edge will have a shearing action for cleaning the seating surface as the valve moves to closed position.

It will be seen that I have devised a relatively simple construction, inexpensive to manufacture and certain in operation, whereby the rise of level of liquid in the float chamber, which is incident to backing up of the water from the sewer, will automatically shut off the connection between the sewer and the drainage conduit leading from the building so that the sewer water cannot back 4 up beyond the float chamber. The device requires no attention for maintenance, and will automatically reopen the connection between the drain pipe and the Sewer as soon as the level of water in the float chamber has receded upon cessation of flood conditions. Even though the mechanism may be inactive for long intervals, any scum or encrustation accumulating on the valve will be scraped clean by the first closing movement of the valve member insuring effective seating thereof.

I claim as my invention:

` 1. In combination with a sewer drain conduit, a chamber interposed therein having an inlet and anr outlet, the inlet entering the chamber above the level of the outlet and terminating in an elbow discharging downwardly in the chamber through a downwardly facing valve seat, a normally open valve disposed out of the path of ow when in open position, said valve being slidable across said seat to close the inlet against backflow, and a float in the chamber with means connecting said oat to said valve for sliding it to closing position over the seat in response to a rise of liquid in the chamber above a predetermined level.

2. In combination with a sewer drain conduit, a chamber interposed therein having a downwardly discharging inlet and an outlet, the inlet terminating in a downwardly facing valve seat disposed above the level of the outlet, a normally open valve disposed out of the path of discharge when in open position, said valve being slidable across said seat, and a float in the chamber with means connecting said float to said valve for sliding it to closing position over the seat in response to a rise of liquid in the chamber above a predetermined level.

3. In combination with a sewer drain conduit, a chamber interposed therein having a downwardly discharging inlet and an outlet, the inlet terminating in a downwardly facing valve seat disposed above the level of the outlet, a valve slidable across said seat, substantially parailel links suspended from the upper part of the chamber supporting said valve by engagement therewith at spaced pivot axes, and a float in the chamber with means connecting said float to said valve for sliding it to closing position over the seat in response to a rise of liquid in the chamber above a predetermined level, said links including spring means tensioned to yieldingly hold the valve to its seat throughout its slide to closing position.

4. In the combination defined in claim 3, said Valve seat having its outer rim beveled to an acute edge engaging the face of the valve for shearing encrusted matter therefrom as the valve moves across said seat.

5. In the combination defined in claim 3, said means connecting the float to the valve including a rock shaft having a pair of arms spaced apart and connected to opposite sides of the lloat respectively, said arms extending in approximately horizontal direction from the rock shaft, and a third arm depending in substantially vertical direction from the rock shaft and connected to the valve.

6. In the combination defined in claim 3, said valve having its leading edge beveled to an acute edge engaging the face of the valve seat for shearing encrusted matter therefrom as the valve moves across said seat.

SAMUEL OLSON. 

